Common Name: foster holly
Type: Broadleaf evergreen
Zone: 6 to 9
Height: 20.00 to 30.00 feet
Spread: 10.00 to 20.00 feet
Bloom Time: April to May
Bloom Description: White
Sun: Full sun to part shade
Suggested Use: Hedge, Shade Tree
Other: Winter Interest, Thorns
Tolerate: Air Pollution
Best grown in organically rich, medium moisture, well-drained, slightly acidic soils in full sun to part shade. Best berry production in full sun. Hollies are dioecious (separate male and female plants). However, foster holly is one of the few hollies in which female plants will produce fruit without fertilization from a male pollinator. Botanically speaking, it is parthenocarpic (from Greek, parthenos meaning virgin and karpos meaning fruit). Therefore, it is unnecessary to purchase a male foster holly for a planting. Foster hollies are not reliably winter hardy throughout USDA Zone 5 and benefit from being sited in protected locations (particularly those sheltered from cold winter winds) in the St. Louis area (Zone 5b to 6a).
Foster holly is the common name attached to five different interspecific hybrids (Ilex cassine x Ilex opaca) introduced into cultivation in the 1950s by E. E. Foster of Foster Nursery in Bessemer, Alabama. Of the five original clones, #1 and #5 are no longer available in commerce, #4 is a male which is uncommonly available (female Foster hollies do not require a male pollinator for fruit development) and #2 and #3 are female plants which are commonly available but are so similar in appearance as to be virtually indistinguishable. Although #2 is by far the most common female clone, nurseries sometimes sell the clones today as male or female Foster hollies without reference to clonal numbers. Foster #2 hollies are currently growing in the Hedge Display at the Kemper Center for Home Gardening. Foster #2 is a small to medium-sized, broadleaf evergreen tree with a dense, upright, pyramidal habit. It typically grows to a mature height of 20-30' tall with a spread of 10-15' unless pruned otherwise. Features glossy, dark olive green, elliptic to obovate, evergreen leaves (2-3" long). Each leaf has 1-5 well-spaced, tiny, spiny, marginal teeth per side. Small white flowers bloom in late spring. Flowers are followed in fall by an abundant and showy crop of bright red berry-like drupes which persist throughout the winter.
No serious insect or disease problems. Susceptible to holly leaf miner, mites, spittlebugs and scale. Chlorosis (yellowing of the leaves) may occur in high pH soils.
Excellent small tree with year-round interest. Good specimen value. Incorporate into a foundation planting. Street tree. Tall screen or hedge.